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Successful Mycoplasma eradication A guide for pig producers and veterinarians
Successful Mycoplasma eradicationA guide for pig producers and veterinarians
Contents
Introduction 3
Planning 4
Farm suitability 5
Eradication options 6-8
Clean practices 9
Monitoring 10
Summary 11
Acknowledgements 12
Enzootic Pneumonia, the respiratory condition caused by Mycoplasma hyopneumoniae (M. hyopneumoniae) is one of the most prevalent diseases in the swine industry worldwide, affecting pigs of all ages and all types of farm or production systems.
The economic losses associated with Mycoplasma infections in pigs are not only related to a decrease in production parameters, such as increases in the number of days to reach slaughter weight, but are also due to the fact that mycoplasmal pneumonia becomes a chronic condition that predisposes pigs to other bacterial and viral respiratory infections. Mycoplasma are also considered to play a central role in Porcine Respiratory Disease Complex (PRDC).
Freedom from M. hyopneumoniae infection is highly desirable as it can reduce costs, minimise losses and improve productivity performance.1,2,3
Mycoplasma eradication programmes, when correctly implemented, have been proven to be highly successful, leading to sustained gains in herd health status and farm profitability. These gains deliver producers a substantial return on investment (ROI) when evaluated against the total costs of implementing the eradication programme.4,5,6
This ROI analysis considers not just the medication costs but it also takes account of the cost of lost (or reduced) production as well as the cost of increased labour and the requisite improvements to farm buildings, equipment and bio-security systems. These related costs substantially exceed the simple cost of treatment. Thus, not only do producers benefit from sustained productivity improvement, but they also profit from an upgraded farm facility.
This Mycoplasma eradication guide is a testament to Novartis Animal Health’s continued commitment to helping swine producers and vets, worldwide, to improve the health status and profit performance of their herds.
The benefits of Mycoplasma eradication
Is complete eradication a realistic objective?
l What is the pig density in my area?
l Do nearby farms or pig truck routes represent a risk to my farm if I eradicate Mycoplasma?
• Epidemiological studies from European countries suggest the airborne transmission of M. hyopneumoniae occurs between farms located within a radius of 2.5-3kms3,7
l Are there any specific seasonal conditions that represent a risk or an advantage if I choose to eradicate?
• Mycoplasma have been observed to survive better in cooler, wetter conditions such as are experienced in temperate climates during the winter months3,7
Can the eradication programme be funded without placing undue pressure on the business?
l In addition to assessing the impact of incremental costs (such as extra labour, repairs, cleaning, equipment and medicines) any financial analysis must also make adjustments for the significant reduction in income that will result from the temporary loss of market pigs
l If total depopulation is financially feasible a source of ‘clean’ pigs must be identified and secured to re-populate the farm
l Finally, the timing of the programme should be planned to optimize the pig flow and minimize losses due to lack of market pigs. Seasonal and market conditions such as weather conditions and peaks and troughs in pork prices should be assessed before deciding when to initiate the programme
Plan carefully before committing to a programme
The first step is to thoroughly assess the financial and logistical impact of starting a Mycoplasma eradication programme.
It is important to remember that each farm is unique and that the extrapolation of the results from eradication programmes implemented within other herds may not necessarily apply.
Prior to committing to an eradication programme key questions need to be asked, and answered affirmatively, to ensure the investment is money well spent.
Is the eradication programme practical? Can it be applied to my pig farm under the given circumstances?
l A farm-specific program is required which is practical, reliable and that can be successfully applied within the framework of the farm management systems. It is important to remember that each farm is unique and what can be applied in one farm may not be valid for the conditions of other swine units
Do not consider an eradication programme unless all the following criteria are met:
l Clinical diagnosis of Mycoplasma is confirmed by demonstration of Mycoplasma hyopneumoniae (usually by PCR) or by suitable serological test (ELISA)
l The farm is situated a safe distance from the biological threat proffered by neighbouring pig farms, pig truck routes and other sources of live pigs infected with Mycoplasma
l Adequate funds are secured to cover the full programme costs and the business cash flow requirements
l A comprehensive bio-security and hygiene programme can be established to avoid re-introduction of infection (for example via vehicle traffic, farm visitors or disease vectors)
l The farm buildings including slurry systems, roofing, flooring and ventilation systems are able to be repaired and returned to good working order
l A supply of Mycoplasma–free replacement stock is available for the future
l All farm personnel are fully committed to the programme
Mycoplasma Eradication Plan Checklist
A plan of attack is needed - the entire farm site and adjacent farm sites should be surveyed before embarking on the eradication program. A farm map should be produced noting the location of all buildings, roads, boundaries, feed stores, pig disposal areas and other landmarks such as lagoons, neighbouring roads and nearby farm buildings (possibly housing or transporting pigs).
l Record the routes taken by feed trucks and other delivery vehicles and devise new clean routes and boundaries
l Weekly task check-lists, with staff and team requirements for each task, need to be compiled
l A detailed list of, and budget for, required repairs, maintenance and replacement work should be made
l Cost, and availability, of all new equipment and supplies required to upgrade the farm should be reviewed
l A large rubbish skip capable of gathering old and replaced debris from around the farm should be placed in an area away from the pigs near the farm boundary
l Quarantine facilities for purchased gilts should be available
l Facilities for the collection of slaughter pigs should be made available and located outside the unit so that trucks that collect pigs do not enter the unit
l Adequate facilities for disposal of pigs should be available and located away from the pig production units
Ensuring the farm is fit for eradication
Eradication options and pig treatment
1) Total depopulation and restocking
This requires the elimination of all animals from the farm followed by thorough cleaning, drying, and disinfection of the entire farm site. Once disinfection and a further drying out is complete then the farm is repopulated with animals certified free of Mycoplasma hyopneumoniae.
This method also provides the opportunity to improve the genetic stock of the herd and/or to eradicate other pathogens (such as PRRSV and APP) by careful selection of replacement stock with appropriate genetic and pathogen-free status.
However total depopulation has a major impact on the supply of market pigs. Even if replacement sows are pregnant, there will still be a minimum of 20 weeks without finished pigs for sale.
This economical loss should be fully assessed, along with the cost of buying in replacement stock, before committing to the programme.
2) Partial depopulation and strategic medication
Pig producers often choose a partial depopulation method because it requires less capital investment. Partial depopulation significantly reduces the loss of market pigs for sale, removes the cost of restocking altogether and conserves the genetic profile of the herd. This method requires the depopulation of farrowing, weaner, grower and finisher premises.
Removal of young animals less than 10 months of age is important to reduce infection pressure in the unit and for the elimination of all shedders from the herd8. Therefore the most reliable results are achieved when for a minimum period of 14 days only breeding animals over 10 months of age may be present in the farm area and these animals are medicated orally daily according to Novartis’ programme for a minimum of 14 days to rid them of any lingering Mycoplasma hyopneumoniae.
Extensive experience shows that Denagard is the drug of choice which, coupled with cleaning and disinfection, can eradicate Mycoplasma in approximately 90% of farms at the first attempt.
Producers have a choice of two different methods of eradication
Pre-planningThere must be a 15 day gap in mating some 100 days before week 1 of the programme. This is designed to achieve a corresponding cessation of farrowing during 14 days of the eradication programme. Depopulation of farrowing, weaner, grower and finisher units at the farm should be planned in good time and carried out until eradication is started. Furthermore, during this period the depopulated area is being cleaned after the pigs are transferred.
Week 1: Preparationl Remove remaining pigs up to 10 months of age from the farm
leaving only adult pigs over 10 months of age
l Empty, clean and disinfect the remaining farrowing, weaner, grower and finisher facilities
l Carefully select and cull pigs to enhance the future farm breeding programme
l Cull or remove all pigs with any sign of disease
l Do not introduce new animals
Weeks 2-3: Medicationl During this 14 day period all remaining breeding animals over 10 months of age are medicated
orally according to Novartis’ programme
l Cull all pigs that refuse to eat their fully medicated diet
l Do not introduce new animals
l No farrowing and subsequent pig flow for a period of 15 days
l During this 14 day medication period thoroughly clean and disinfect once or twice daily in the area where the animals are. Slurry canals should be emptied and disinfected during this period. Effective rodent control should be established before eradication is started.
After finalization of medication / production normalisationl The whole farm site is now clean and working. New litters may now be born and processed
l New Mycoplasma-free pigs can be introduced onto the farm
Model for partial depopulation and strategic medication
BoarShed FarrowingHouse Dry
Sow
Boar
Shed
Farrowing
HouseDrySow
BoarShed
FarrowingHouse
DrySow
Boar
Shed
Farrowing
House
DrySow
Dead PigChiller
Workshop
Laneway
Effluent Ponds
Car Park
CLEAN AREA DIRTY AREA
Office
Water
Ramp
Gas
AI Storage
EmergencyEvacuation Point
MedicationStorage
Partial depopulation - site plan
3) Modified partial depopulation
There are several modifications of this programme the purpose of which is to minimize loss of production and to extend the programme to include the elimination of other diseases
l For some large multi-site farms a modified partial depopulation method has been successfully deployed to minimize production downtime. Sometimes the medication procedure includes piglets before weaning up to four weeks. Only piglets born after 14 days oral medication of breeding animals can repopulate the depopulated area. This procedure is well suited to a multi-site production system where the eradication procedure can be carried out on site 1 with only breeding animals older than 10 months and complete depopulation and repopulation of sites 2 and 3 (Figure 1)9
l Sometimes animals under 10 months of age remain in the farm during eradication, but the rate of success will decrease by decreasing age limits
l This programme can be used for elimination of other diseases, such as swine dysentery, mange etc9
l This programme combines the design of the partial depopulation method with some additional disease eradication strategies such as herd closure, stabilization of the sow herd immunological status, and off-site early weaning
Breeder units
Overstock your sow inventory. Ensure 100% sero-conversion of the entire breeding herd. Keep only animals older than 10 months of age.
Early weaning transfer
A large group of pigs are weaned at the earliest age possible, and moved onto the separate, and clean weaner-nursery sites. This must be done on an all-in, all-out basis. All piglets should be injected with Denagard at the time of transfer.
Biosecure all-in, all-out practices
The new clean pigs at the weaner sites, and at their subsequent grower-finisher sites, must be kept in strict bio-secure, separate and isolated all-in, all-out sites to ensure that re-infections with Mycoplasma do not occur.
This modified approach offers the most advantages from the pig production flow point of view. However, as there is a lack of depopulation in grower and finishing sites, the risk of Mycoplasma re-infection is greater.
What is the best Denagard dose for your farm?
The principle of eradication is the removal of 100% of Mycoplasma hyopneumoniae from 100% of pigs remaining on the farm. Denagard dosage and treatment duration can vary, depending on the farm conditions and results of susceptibility tests.
Example of Denagard standard medication programme (eradication)
Application Dosage
Breeding oral 6-8 mg thf */ kg bw, animals 14 days
Eradication options continued
Figure 1: Multi-site production system – modified partial depopulation
Site 1 Breeding, Gestation, FarrowingStrategic medication
Site 2 7-30kgWeaner Depopulation
Site 3 30-100kgFinisher Depopulation
* thf – tiamulin hydrogen fumarate (Denagard)
The epidemiology of Mycoplasma hyopneumoniae is not fully understood. Field observations suggest that airborne transmission is possible up to a distance of 3 km.
Mycoplasma hyopneumoniae is generally considered a ‘pig-associated’ bacterium, which only lives a short time outside the host pig, and requires certain climatic conditions (fresh and humid weather) in order to remain viable.
Correct cleaning consists of:
l Washing all surfaces with soapy detergent and water to ensure the removal of all organic matter
l Drying the washed surfaces completely
l Applying a disinfectant capable of killing Mycoplasma (eg quarternary ammonia)
When cleaning and disinfecting, the hotter and drier the weather, the better as this will assist drying. Shed panels may be removed to aid drying
The role of vectors in the transmission of M. hyopneumoniae has not been evaluated. However, any mechanical vector should be considered as a risk for uninfected farms.10,11,12 To this end, expert assistance should be sought to make sure all rodents and birds are killed and removed from the farm
Clean, disinfect, and adopt new ‘clean’ practices
l Remove all bedding materials, such as straw, during the eradication
l Remove rubbish from inside and outside the premises
l Empty, clean, disinfect and dry holding tanks and slurry canals
l Shift, clean and disinfect slats, slurry gates and other heavy parts of the slurry system
l Wash all surfaces, inside and outside the pig sheds, with soapy detergent to ensure removal of all organic matter
l Clean and disinfect tools, footwear and other ‘vehicles’
l Dry the washed surfaces completely
l Disinfect the farm site (including vehicles and equipment) with appropriate disinfectant
Although Mycoplasma transmission by rodents, flies, birds, or any vectors has not been established, it would be wise to adopt pest control programmes to enhance the bio-security status of the site. This is especially important for the eradication of other pathogens as well as improving the overall herd health status.
Cleaning and disinfection checklist:
The introduction of a small group of naive pigs and their subsequent evaluation is another effective means to monitor the herd for ongoing freedom from infection.
Monitor success and remain vigilant to disease threats
After the cessation of treatment Mycoplasma hyopneumoniae monitoring should be carried out to ensure the clean status of the farm by using suitable laboratory tests, clinical evaluation and post-mortem examination.
To ensure the farm remains free from Mycoplasma hyopneumoniae it is essential to:
l Lock gates at the farm entrance with appropriate signage to prevent uninvited farm visitors. While many people will want to see the ‘new’ farm - don’t let them!
l Rapidly assess any pig with possible clinical signs of Mycoplasma so effective measures can be taken to protect the herd
l Regularly monitor the herd by checking lung samples at the slaughter house
l Buy only pigs from farms which are free from Mycoplasma hyopneumoniae
Maintaining ‘Mycoplasma-free’ status
Summary
Important questions to ask before embarking on eradication programmes:
l Is the eradication realistically achievable?
l Is everyone, including every single staff member, 100% committed to achieving the objective?
l Is the eradication programme economically viable?
Key benefits of a Mycoplasma eradication programme:
l Long-term productivity gains due to improved production performance and reduced disease incidence
l Increased profitability due to reduced medical and veterinary costs
l Long-term improvement in the overall herd health performance. This is due to a reduced risk of PRDC and other disease conditions predisposed by infection with Mycoplasma hyopneumoniae
l An upgraded pig production facility with lasting bio-security benefits
Choosing the right eradication approach
Every farm or production site has a unique set of circumstances that must be evaluated prior to selecting the best approach and the required treatment protocol. Expert advice is therefore advised to ensure all, financial, veterinary and bio-security issues are professionally addressed.
There is a choice of eradication programmes, as outlined on pages 6-8:
Total depopulation – this involves removing all the animals from the farm site, the cleaning and disinfecting of the site and the subsequent introduction of replacement breeding stock known to be free from Mycoplasma hyopneumoniae infection.
Partial depopulation and strategic medication l For a minimum period of 14 days on site 1
(breeding, gestation, farrowing) only breeding animals older than 10 months remain in the herd. All young animals are moved out from the herd area while farrowing is stopped for 14 days
l All remaining breeding animals are medicated orally, daily, with suitable antimicrobial/s for a minimum of 14 days
l Thorough cleaning and disinfection is conducted once or twice daily in the area where the animals remain while all depopulated pens are cleaned and disinfected
l Depopulation of weaners and finishers on sites 2 and 3 is followed by cleaning and disinfection, after which the units must be left empty for 21 days
Ensuring success
Key to the success of the programme is planning, timing and the total commitment of all personnel. Effective planning and timing will ensure the programme is effectively deployed minimizing lost production and maximising income.
It is essential that the site infrastructure is upgraded to a level that sustains the programme and which facilitates the adoption of the best possible bio-security practices going forward.
Minimising the threat of re-infection from neighbouring, introduced or passing stock is mandatory.
Novartis Technical Support
Novartis is 100% committed to supporting pig producers around the world. For more information or assistance please view our website at www.denagard.com for a full list of helpful contacts.
Denagard® is a registered trademark of Novartis AG, Basel, Switzerland.Label indications, dosage rates and withdrawal periods may vary by country.Please refer to label in your country for approved usage instructions.©2009 Novartis Animal Health Inc. 20080063
Novartis Animal Health Inc., PO Box CH-4002, Basel, Switzerland.Tel: +41 61 697 57 35 Fax: +41 61 697 67 88www.denagard.com
Acknowledgements
This eradication guide has been reviewed and accepted by the Denagard Advisory Board and Maria Pieters (University of Minnesota).
Eradication is not guaranteed, but has been achieved on many sites around the world when these guidelines have been strictly adhered to.
Novartis Animal Health is fully committed to helping pig producers to enhance the health status, and productivity, of their herds.
References
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3. Ross D. (1999). Mycoplasmal Diseases. In: Diseases of Swine. 8th Edition. Iowa State Press. p. 495-509.
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5. J.B.Lorenzen (2000). Proc. 16th IPVS Congress, Melbourne, Australia P.340
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